Increasingly stringent requirements for isolation of new buildings, population growth and increased comfort requirements for indoor temperatures have led to increasing cooling needs in society. Conventional refrigerators are normally powered by electricity that increases the need for energy. An alternative technique that uses significantly less energy is to store snow and ice during the winter and use this for cooling in the summer. This technique has the potential to be used in most temperate climate zones in the world.

This master thesis has looked into the newly created snow storage plant, which has been built in connection with the expansion of Oslo Airport. There are only two similar in the world, at Sundsvall Hospital and Sapporo Airport respectively. The study is based on the first year of testing that took place in the summer of 2016 and will be able to help meet the peak demand for cooling at the newly opened terminal from the summer of 2017. The calculations carried out in connection with this analysis are derived from the logging data from the measuring instruments which were assumed to have the greatest potential to evaluate the first year's operation of the plant.

It was estimated that after the cover phase there were about 30000m3 of snow in the pool which corresponds to about 2000 MWh of stored cooling energy in the snow storage. The results of cooling delivery at the first year of operation were somewhere between 427 and 809 MWh, depending on whether the energy meter was read or calculated using the collected data. This gave a total efficiency of either 7.3 or 13.9 depending on the amount of energy used and a system loss of 79% or 60% respectively.

The easiest measure to reduce the loss in the system will be to drain excess water in the plant from the return water rather than drain cold melt water straight from the pool which was done during the summer of 2016. This can reduce the energy loss by nearly 200 MWh a year.

The major discrepancy between reading and calculated value should be explored further, especially because the plant is controlled according to the values from the logging data. It may be considered to replace the temperature sensors before and after the exchanger with sensors that has higher accuracy than those installed today. This may lead to better system control.

The LCOE for the plant was estimated to be 2.79 NOK/kWh which must be considered to be high. This is mainly attributable to high investment costs, mainly driven by additional costs associated with construction work at an operating airport.

During the lifetime of the plant it will produce almost 17 GWh more renewable cooling than conventional cooling application could do and will help reduce the CO2 emissions footprint of OSL.

The acquired experience as a result of the creation of a snow cooling plant on OSL can help to realize similar systems to be established elsewhere. Some potential locations that could exploit this technology are airports, industrial areas, hospitals, data centers or at snow landfills near areas with high cooling needs.

Publisher

Norwegian University of Life Sciences, Ås

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